I have a set of large coilsprings that I am using for a project. I want to weaken them a little. What is the best method?. thank you.

Heat and cool slowly? Not sure how much you want to weaken them.

Safely provide direct flame to them.

I hit an end coil (1) with a cutting torch in a few seconds (15) it will get red and unwind a bit.
Do a few and you should get it dailed in.

The cutting torch has a small direct flame and hitting one coil gives you more control.

One of those hand held brenz-O- matice torches will do the trick. I heat the entire spring for about 30 seconds On a larger spring you may have to heat them longer .. It doesn't have to get cherry red to get It done. I've done 100s 1 1/2s traps this way

Maybe grind/file across the coils until you get what you want?

Thanks for all the advice. Going to give it a try this weekend.

How about just taking one spring off. I would hate to see you damage a good spring. In fact if you don't like that idea just post on here for some used ones or even trade with someone that wants good springs.......jk

So if I do this to 1 1/2 coils. Will they still hold rats and mink .

Yup, removing one spring or softening a coil or two will still hold muskrats, don't know about mink as I never caught one.